APPARATUS FOR REDUCING POLYMER DEPOSITION ON SUBSTRATE SUPPORT

Description

Field of the Invention

[0001] The invention relates to an apparatus and method for reducing polymer buildup in a plasma processing chamber, and more particularly, the invention relates to the introduction of clearance gas into a gap in a substrate holder to avoid polymer deposition on exposed surfaces of the substrate holder.

Background of the Invention

[0002] Vacuum processing chambers are generally used for chemical vapor depositing (CVD) and etching of materials on substrates by supplying process gas to the vacuum chamber and application of an RF field to the gas. Examples of parallel plate, inductively coupled plasma (TCP™, also called ICP), and electron-cyclotron resonance (ECR) reactors are disclosed in commonly owned U.S. Patent Nos. 4,340,462; 4,948,458; and 5,200,232. The substrates are held in place within the vacuum chamber during processing by substrate holders. Conventional substrate holders include mechanical clamps and electrostatic clamps (ESC). Examples of mechanical clamps and ESC substrate holders are provided in commonly owned U.S. Patent No. 5,262,029 and commonly owned U.S. Application No. 08/401,524 filed on March 10, 1995. Substrate holders in the form of an electrode can supply radiofrequency (RF) power into the chamber, as disclosed in U.S. Patent No. 4,579,618. EP 0 668 607 A describes a vacuum chamber for processing substrates in which a substrate is supported on an electrostatic chuck and gas supply means are provided for introducing a non-reactive masking gas to protect the periphery of the chuck from the process gas.

[0003] Substrates which are etched in an oxide etching process generally include an underlayer, an oxide layer which is to be etched, and a photoresist layer formed on top of the oxide layer. The oxide layer may be one of SiO₂, BPSG, PSG, or other oxide material. The underlayer may be Si, TiN, silicide, or other underlying layer or substrate material. During processing of substrates, unwanted polymer deposition on the surfaces of the chamber can occur. For instance, when the chamber heats up to above 80°C during oxide etching, a reaction can occur wherein CF₃ forms CF₂ and HF. The formation of CF₂ leads to an increase in polymer deposition on surfaces within the chamber. These deposits may be removed between successive processing of wafers to provide more consistent processing of the wafers.

[0004] During etching of a substrate such as a semiconductor wafer in a plasma reactor, the polymer can build up on the cooled, exposed surfaces of the chamber including exposed surfaces of a substrate support such as an electrostatic chuck and other surfaces such as a dielectric annular cap/focus ring surrounding the substrate support. This buildup may cause problems if it flakes off and is carried onto the top surface of the electrostatic chuck. These contaminants on the top surface of the chuck can prevent the chuck from operating properly to hold the wafer securely. In addition, the contaminants can allow helium which is supplied under the wafer as a cooling medium to leak from beneath the wafer and reduce the wafer cooling. The contaminants can also be deposited on and adversely affect the wafer itself. The buildup of polymer can be removed by a cleaning step performed between the processing of successive wafers. Generally, cleaning can be performed by injecting oxygen into the chamber, striking a plasma and reacting the oxygen with the deposited polymer to achieve an aggressive oxygen clean of the processing chamber.

[0005] One area in which deposits of polymer can occur in a processing chamber is a narrow gap between the electrostatic chuck on which the wafer is supported and a focus ring which surrounds the electrostatic chuck. This gap allows for differences in manufacturing tolerances and thermal expansion of the chuck and focus ring. However, process gas and volatile byproducts within the chamber may migrate into the gap and cause undesirable polymer deposits in this area which may flake off and cause contamination of the wafer and/or chamber.

[0006] The aggressive oxygen cleaning of the processing chamber is undesirable because it adds to the wafer cycle time, reducing through-put of the system. In addition, the aggressive oxygen clean will shorten the lives of members within the processing chamber including the electrostatic clamp and focus ring due to ion bombardment of these members. As such, it would be desirable if substrate processing could be carried out without a need for the aggressive oxygen cleaning step to thereby shorten cycle time and extend the life of chamber components.

Summary of the Invention

[0007] The present invention addresses the problem of deposition of polymer in a plasma processing chamber by providing a clearance gas stream which reduces polymer build-up on the substrate support.

[0008] According to one aspect of the present invention, a plasma processing apparatus comprises a processing chamber; a power source which energizes process gas in an interior of the processing chamber into a plasma state; a substrate support supporting a substrate within the interior of the processing chamber for processing by the process gas, the substrate support having an outer surface with the substrate being supported in an overhanging relationship relative to the outer surface of the support; a focus ring surrounding the substrate support, the focus ring having an inner surface forming a gap between the outer surface of the substrate support and the focus ring, the gap being in fluid communication with the interior of the processing chamber with the substrate extending over at least part of the focus ring such that the inner surface of the focus ring is disposed inwardly of an outer periphery of the substrate; and a clearance gas supply in fluid communication with the gap via a plurality of radial supply channels in the support having outlets in the gap, the gas supply serving to supply clearance gas to the gap to block migration of process gas and volatile byproducts thereof into the gap during processing of the substrate.

[0009] According to another aspect of the invention there is provided a substrate support for a plasma processing apparatus having a processing chamber, a power source which energizes process gas in an interior of the processing chamber into a plasma state for processing a substrate and a clearance gas supply, the substrate support comprising:

a substrate support surface which supports a substrate within the interior of the processing chamber during use, the substrate support surface being delimited by an outer surface and the substrate being supported in overhanging relationship to the support surface to extend beyond the outer surface; a focus ring supported on and surrounding the substrate support surface, the focus ring having an inner surface forming a gap between the outer surface of the substrate support and the focus ring, the gap being in fluid communication with the interior of the processing chamber when the substrate support is mounted in the processing chamber with the substrate extending over at least part of the focus ring such that the inner surface of the focus ring is located inwardly of an outer periphery of the substrate; and fluid communication means including a plurality of radial channels in the support having outlets in the gap for establishing fluid communication between the gap and the clearance gas supply which serves during use to supply clearance gas to the gap at a flow rate which is sufficient to block migration of process gas and volatile byproducts thereof into the gap during processing of a substrate supported on the substrate support surface.

[0010] According to a further aspect of the present invention, a method of controlling polymer deposition within a plasma processing chamber comprises placing a substrate on a substrate support within the processing chamber; energizing process gas in an interior of the processing chamber into a plasma state for processing the substrate; and introducing a clearance gas supplied by a gas supply into a gap between the substrate holder and a focus ring supported by and surrounding the substrate support with the substrate extending over at least part of the focus ring such that an inner surface of the focus ring defining the gap is located inwardly of an outer periphery of the substrate, the clearance gas being supplied via radial channels in the support leading to outlets in the gap at a flow rate sufficient to minimize migration of process gas and volatile byproducts thereof into the gap.

[0011] Other preferred features of the invention are defined in the dependent claims.

Brief Description of the Drawings

[0012] The invention will be described in greater detail with reference to the accompanying drawings in which like elements bear like reference numerals, and wherein:

FIG. 1 is a cross sectional view of a vacuum processing chamber;

FIG. 2 is an enlarged cross sectional view of a portion of FIG. 1 showing the space between the electrostatic chuck and the focus ring; and

FIG. 3 is an enlarged cross sectional view of an alternative embodiment of the invention.

Detailed Description of the Preferred Embodiments

[0013] A vacuum processing chamber according to one embodiment of the present invention is illustrated in FIG. 1. The vacuum processing chamber 10 includes a substrate holder 12 including an electrode providing an RF bias to a substrate supported thereon. The substrate holder 12 includes an electrostatic clamp 14 for clamping the substrate. The substrate which is placed on the electrostatic clamp is preferably cooled by helium backcooling (not shown) provided between the substrate and the electrostatic clamp. A ceramic focus ring 16 surrounds the electrostatic clamp 14.

[0014] The vacuum processing chamber includes a source of energy for maintaining a high density (e.g. 10¹¹-10¹² ions/cm³) plasma in the chamber such as an antenna 18 (such as a planar spiral coil or other suitable design) which is positioned above the chamber and powered by a suitable RF source. A suitable RF impedance matching circuit inductively couples RF energy into the chamber 10 so as to provide a high density plasma. The chamber 10 also includes a suitable vacuum pumping apparatus for maintaining the interior of the chamber at a desired pressure (e.g. below 50 mTorr, typically 1-20 mTorr). A dielectric window 20 (such as a uniformly thick and planar sheet of quartz, alumina, silicon nitride, etc.) is provided between the antenna 18 and the interior of the processing chamber 10 and forms the vacuum chamber wall at the top of the processing chamber 10. A dielectric gas distribution plate, commonly called a showerhead 22, may be provided beneath the window 20 and includes a plurality of openings such as circular holes (not shown) for delivering process gas supplied by a gas supply to the processing chamber 10. However, the gas distribution plate 22 can be omitted and process gas can be supplied to the chamber by other arrangements such as gas rings, etc.

[0015] FIG. 2 is an enlarged cross sectional view of an outer portion of the electrostatic chuck 14 and the focus ring 16 and illustrates a narrow space 30 (e.g., less than 0.4 mm (1/4 inch)) which is provided between the two members. The annular space 30 provides clearance between an inner surface 46 of the focus ring and an outer surface 48 of the electrostatic chuck 14 to allow for manufacturing tolerances and the different thermal expansions of the elements. A substrate in the form of a semiconductor wafer 32 is positioned on the electrostatic chuck 14 and held in place by a suitable electrostatic clamping force. A small vertical clearance space 34 is provided between an overhanging edge of the wafer 32 and a groove 36 provided in the edge of the focus ring 16. This vertical clearance space 34 is designed to prevent the overhanging edge of the wafer 32 from being lifted and thereby avoid a reduction in clamping force applied by the electrostatic chuck.

[0016] According to the present invention, a flow of a clearance gas such as helium gas from a clearance gas supply 50 is provided to the annular space 30 to prevent entry of process gas and volatile byproducts thereof through the vertical clearance space 34 into the annular space 30. The flow of the clearance gas minimizes deposition of polymer within the annular space 30 which may flake off and be carried onto the top surface of the chuck or onto the substrate during processing. According to the invention , the flow of the clearance gas is provided by a series of radially extending channels 38 in the electrostatic chuck 14. The channels 38 have orifices 40 spaced around the circumference of the electrostatic chuck 14 and provide clearance gas to the annular space 30. As shown in FIG. 1, the channels 38 may be connected to an axially extending central passage 54 through which the clearance gas is delivered.

[0017] As an example, clearance gas can be provided to the annular space 30 through eight radially extending channels 38. However, any number of channels in the electrostatic chuck 14 may also be used to deliver the clearance gas to the annular space 30. Further, one or more clearance gas delivery channels may be formed in the focus ring for delivery of clearance gas to the annular space 30 or helium can be supplied to the space 30 through supply passages in the chuck 14 and ring 16.

[0018] According to the present invention, a clearance gas flow rate is used which is sufficiently high to block migration of process gas and volatile byproducts thereof into the annular space 30 from the processing chamber. However, in the case of plasma etching, it is preferred that the gas flow rate must not be so high as to adversely affect edge etch performance by the presence of a gas expansion plume at the edge of the substrate. An example of an appropriate helium gas flow rate during oxide etching is 40 to 120 standard cubic centimeters per minute (SCCM), preferably 60 to 100 SCCM, and more preferably around 75 to 85 SCCM, and will depend on the particular dimensions and application of a particular processing chamber. In one tested processing chamber configuration for oxide etching 200 cm wafers, 80 SCCM of helium gas was found to accomplish the required exclusion of process gas yet did not disturb the processing of the wafer.

[0019] According to the embodiment of the invention shown in FIG. 2, the flow of clearance gas is provided by a fixed pressure clearance gas supply 50. The gas flow rate can also be controlled by insertion of hollow screws 42 into the orifices 40. For instance, the hollow screws can be provided with a jewel orifice plate 44 which has an opening with a desired diameter to achieve the desired gas flow rate into the annular space. The diameter of the opening in the orifice plate which is selected to achieve the desired flow rate will depend on various process conditions such as the type of process being carried out (etching, deposition, photoresist stripping, etc.), the pressure of the clearance gas supply, the size of the annular space, and the number of channels 38, etc.

[0020] According to another embodiment of the invention, as shown in FIG. 3, a mass flow controller 52 is connected to the clearance gas supply 50 for varying the gas flow rate to the channels 38. In this embodiment, the hollow screws 42 with the jewel orifice plates 44 may be omitted because the flow rate is easily controlled either manually or automatically by the mass flow controller. In this embodiment, the orifices 40 have a constant diameter.

[0021] Although the invention has been described as employing helium gas for preventing process gas from entering the annular space 30, it should be understood that helium gas has been used by way of example only. Other gasses may also be used provided they will not affect the wafer processing operation which is being performed within the processing chamber.

[0022] While the invention has been described in detail with reference to a preferred embodiment thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed without departing from the scope of the invention as defined in the claims.

Claims

1. A plasma processing apparatus comprising:

a processing chamber (10);

a power source which energizes process gas in an interior of the processing chamber into a plasma state;

a substrate support (14, 12) supporting a substrate (32) within the interior of the processing chamber for processing by the process gas, the substrate support having an outer surface with the substrate being supported in an overhanging relationship relative to the outer surface of the support;

a focus ring (16) surrounding the substrate support, the focus ring having an inner surface forming a gap (30) between the outer surface of the substrate support and the focus ring, the gap (30) being in fluid communication with the interior of the processing chamber with the substrate extending over at least part of the focus ring such that the inner surface of the focus ring is disposed inwardly of an outer periphery of the substrate; and

a clearance gas supply (50) in fluid communication with the gap via a plurality of radial supply channels (38) in the support, having outlets in the gap, the gas supply serving to supply clearance gas to the gap to block migration of process gas and volatile byproducts thereof into the gap during processing of the substrate.

2. A plasma processing apparatus according to claim 1, wherein the power source comprise a coil (18) which inductively couples RF power through a dielectric window (20) to form a high density plasma in the processing chamber.

3. A plasma processing apparatus according to claim 1 or 2, wherein the clearance gas supply supplies helium to the gap.

4. A plasma processing apparatus according to claim 1, 2, or 3, wherein the clearance gas supply supplies the clearance gas at a flow rate of 60 to 100 sccm.

5. A plasma processing apparatus according to any one of claims 1 to 4, wherein the gap is annular and there are eight radial supply channels.

6. A plasma processing apparatus according to any one of claims 1 to 5, wherein the supply channels (38) are provided with flow restricting portions (40, 41, 42) for controlling the flow rate of the clearance gas.

7. A plasma processing apparatus according to any one of claims 1 to 6, wherein the support is composed of a holder (12) and an electrostatic clamp (14) and the channels (38) are in the clamp.

8. A plasma processing apparatus according to any one of claims 1 to 7, wherein the focus ring is made from ceramic and the gap is less than 6.4 mm (¼ inch) between the inner and outer surfaces.

9. A substrate support for a plasma processing apparatus having a processing chamber (10), a power source which energizes process gas in an interior of the processing chamber into a plasma state for processing a substrate and a clearance gas supply (50), the substrate support comprising:

a substrate support surface which supports a substrate (32) within the interior of the processing chamber during use, the substrate support surface being delimited by an outer surface and the substrate being supported in overhanging relationship to the support surface to extend beyond the outer surface;

a focus ring (16) supported on and surrounding the substrate support surface, the focus ring having an inner surface forming a gap between the outer surface of the substrate support and the focus ring, the gap being in fluid communication with the interior of the processing chamber when the substrate support is mounted in the processing chamber with the substrate extending over at least part of the focus ring such that the inner surface of the focus ring is located inwardly of an outer periphery of the substrate; and

fluid communication means including a plurality of radial channels (38) in the support having outlets in the gap for establishing fluid communication between the gap and the clearance gas supply which serves during use to supply clearance gas to the gap at a flow rate which is sufficient to block migration of process gas and volatile byproducts thereof into the gap during processing of a substrate supported on the substrate support surface.

10. A substrate support according to claim 9, wherein the substrate support surface is provided by an electrostatic chuck (14) and the focus ring is ceramic.

11. A substrate support according to claim 9, wherein the gap (30) is annular and there are eight radial channels in the chuck with outlets in the gap.

12. A substrate support according to claim 11, wherein the clearance gas channels are provided with flow restricting portions (40, 41, 42) for controlling the flow rate of the clearance gas.

13. A method of controlling polymer deposition within a plasma processing chamber (10) comprising:

placing a substrate (32) on a substrate support (14, 12) within the processing chamber (10);

energizing process gas in an interior of the processing chamber into a plasma state for processing the substrate; and

introducing a clearance gas supplied by a gas supply (50) into a gap (30) between the substrate holder and a focus ring (16) supported by and surrounding the substrate support with the substrate extending over at least part of the focus ring such that an inner surface of the focus ring defining the gap is located inwardly of an outer periphery of the substrate, the clearance gas being supplied via radial channels (38) in the support leading to the outlets in the gap at a flow rate sufficient to minimize migration of process gas and volatile byproducts thereof into the gap.

14. A method according to claim 13, wherein the support is composed of a holder (12) and an electrostatic chuck (14), the substrate is held in place within the processing chamber by the electrostatic chuck, and the process gas is energized into the plasma state by a power source which supplies RF power to a coil which inductively couples the RF power through a dielectric window to form a high density plasma in the processing chamber.

15. A method according to claim 13 or 14, wherein the clearance gas introduced into the gap comprises helium.

16. A method according to any one of claims 13 to 15, wherein the clearance gas is introduced at a flow rate of 60 to 100 sccm.

17. A method according to any one of claims 13 to 16, wherein the substrate is etched by the process gas and the clearance gas is supplied at a flow rate which does not adversely affect etch edge performance.

Ansprüche

1. Eine Plasmabehandlungsvorrichtung, umfassend:

eine Behandlungskammer (10);

eine Leistungsquelle, welche Prozessgas in einem Inneren der Behandlungskammer in einen Plasmazustand energetisiert;

einen Substratträger (14, 12), welcher ein Substrat (32) innerhalb des Inneren der Behandlungskammer zum Behandeln durch das Prozessgas trägt, wobei der Substratträger eine äußere Oberfläche aufweist, und das Substrat in einer überstehenden Beziehung relativ zu der äußeren Oberfläche des Trägers getragen wird;

einen Fokusring (16), welcher den Substratträger umschließt, wobei der Fokusring eine innere Oberfläche aufweist, welche eine Lücke (30) zwischen der äußeren Oberfläche des Substratträgers und des Fokusrings bildet, die Lücke (30) steht in einer Strömungsverbindung mit dem Inneren der Prozesskammer, wobei sich das Substrat über wenigstens einen Teil des Fokusrings derart erstreckt, dass die innere Oberfläche des Fokusrings innerhalb eines äußeren Umfangs des Substrats angeordnet ist; und

eine Spaltgas-Versorgung (50), welche in Strömungsverbindung mit der Lücke über eine Vielzahl von radialen Versorgungskanälen (38) in dem Träger steht, welche Auslässe in der Lücke haben, wobei die Gasversorgung dazu dient, Spaltgas in die Lücke zuzuführen, um ein Austreten von Prozessgas und von flüchtigen Nebenprodukten desselben in die Lücke während der Behandlung des Substrates zu blockieren.

2. Eine Plasmabehandlungsvorrichtung gemäß Anspruch 1, wobei die Leistungsquelle eine Spule (18) umfasst, welche induktiv eine HF-Leistung durch ein dielektrisches Fenster (20) einkoppelt, um ein Plasma mit hoher Dichte in der Behandlungskammer auszubilden.

3. Eine Plasmabehandlungsvorrichtung gemäß Anspruch 1 oder 2, wobei die Spaltgas-Versorgung Helium in die Lücke zuführt.

4. Eine Plasmabehandlungsvorrichtung gemäß Anspruch 1, 2 oder 3, wobei die Spaltgas-Versorgung das Spaltgas mit einer Strömungsrate von 60 bis 100 sccm zuführt.

5. Eine Plasmabehandlungsvorrichtung gemäß einem der Ansprüche 1 bis 4, wobei die Lücke ringförmig ist und es acht radiale Versorgungskanäle gibt.

6. Eine Plasmabehandlungsvorrichtung gemäß einem der Ansprüche 1 bis 5, wobei die Versorgungskanäle (38) mit Strömungsbeschränkungsbereichen (40, 41, 42) versehen sind, zum Steuern der Strömungsrate des Spaltgases.

7. Eine Plasmabehandlungsvorrichtung gemäß einem der Ansprüche 1 bis 6, wobei der Träger aus einem Halter (12) und einer elektrostatischen Klemme (14) zusammengesetzt ist und die Kanäle (38) in der Klemme ausgebildet sind.

8. Eine Plasmabehandlungsvorrichtung gemäß einem der Ansprüche 1 bis 7, wobei der Fokusring aus Keramik hergestellt ist und die Lücke weniger als 6,4 Millimeter (1/4 inch) zwischen den inneren und äußeren Oberflächen beträgt.

9. Ein Substrathalter für eine Plasmabehandlungsvorrichtung, welche eine Behandlungskammer (10) aufweist, ferner eine Leistungsquelle, welche das Prozessgas in einem Inneren der Behandlungskammer in einen Plasmazustand zum Behandeln eines Substrats energetisiert, und ferner eine Spaltgas-Versorgung (50), wobei der Substratträger umfasst:

eine Substrattragoberfläche, welche ein Substrat (32) innerhalb des Inneren der Behandlungskammer während der Verwendung trägt, wobei die Substrattragoberfläche abgegrenzt ist durch eine äußere Oberfläche und das Substrat in einer überstehenden Beziehung zu der Substratoberfläche getragen wird, um sich über die äußere Oberfläche hinaus zu erstrecken; einen Fokusring (16), welcher auf der Substrattragoberfläche getragen wird und diese umschließt, wobei der Fokusring eine innere Oberfläche aufweist, weiche eine Lücke zwischen der äußeren Oberfläche des Substratträgers und dem Fokusring ausbildet, und die Lücke in Strömungsverbindung mit dem Inneren der Behandlungskammer steht, wenn der Substratträger in der Prozesskammer montiert ist, wobei sich das Substrat über wenigstens einen Teil des Fokusrings derart erstreckt, dass die innere Oberfläche des Fokusrings innerhalb eines äußeren Umfangs des Substrats positioniert ist; und

ein Strömungsverbindungsmittel, umfassend eine Vielzahl von radialen Kanälen (38) in dem Träger, welche Auslässe in der Lücke aufweisen, zum Herstellen einer Strömungsverbindung zwischen der Lücke und der Spaltgas-Versorgung, welches während der Verwendung dazu dient, Spaltgas in die Lücke mit einer Strömungsrate zuzuführen, welche ausreichend ist, um das Austreten von Prozessgas und flüchtigen Nebenprodukten desselben in die Lücke während des Behandeln eines Substrats, welches auf der Substrattragoberfläche getragen wird, zu blockieren.

10. Ein Substratträger gemäß Anspruch 9, wobei die Substrattragoberfläche durch ein elektrostatisches Futter (14) hergestellt wird und der Fokusring aus Keramik ausgebildet ist.

11. Ein Substratträger gemäß Anspruch 9, wobei die Lücke (30) kreisförmig ist und es acht radiale Kanäle in dem Futter mit Auslässen in der Lücke gibt.

12. Ein Substratträger gemäß Anspruch 11, wobei die Spaltgas-Kanäle mit Strömungseinschränkungsbereichen (40, 41, 42) versehen sind, zum Steuern der Strömungsrate des Spaltgases.

13. Ein Verfahren des Steuerns der Polymerabscheidung innerhalb einer Plasmabehandlungskammer (10), umfassend:

das Positionieren eines Substrats (32) auf einem Substrathalter (14, 12) innerhalb der Behandlungskammer (10);

das Energetisieren von Prozessgas in einem Inneren der Behandlungskammer in einen Plasmazustand zum Behandeln des Substrats; und

das Einführen eines Spaltgases, welches durch eine Gasversorgung (50) zugeführt wird, in eine Lücke (30) zwischen dem Substrathalter und einem Fokusring (16), welcher durch den Substratträger getragen wird und diesen umschließt, wobei das Substrat sich über wenigstens einen Teil des Fokusrings derart erstreckt, dass eine innere Oberfläche des Fokusrings, welche die Lücke bildet, innerhalb eines äußeren Umfangs des Substrats positioniert ist, das Spaltgas wird über radiale Kanäle (38) in den Träger, welche zu Auslässen in der Lücke führen, mit einer Strömungsrate zugeführt, welche ausreichend ist, um das Austreten von Prozessgas und flüchtigen Nebenprodukten desselben in die Lücke zu minimieren.

14. Ein Verfahren gemäß Anspruch 13, wobei der Träger aus einem Halter (12) und einem elektrostatischen Futter (14) zusammengesetzt ist, das Substrat an seinem Platz innerhalb der Behandlungskammer durch das elektrostatische Futter gehalten wird und das Prozessgas in den Plasmazustand durch eine Leistungsquelle energetisiert wird, welche HF-Leistung zu einer Spule zuführt, welche induktiv die HF-Leistung durch ein dielektrisches Fenster einkoppelt, um einen Plasmazustand mit hoher Dichte in der Behandlungskammer auszubilden.

15. Ein Verfahren gemäß Anspruch 13 oder 14, wobei das Spaltgas, welches in die Lücke eingeführt wird, Helium umfasst.

16. Ein Verfahren gemäß einem der Ansprüche 13 bis 15, wobei das Spaltgas in die Lücke mit einer Strömungsrate von 60 bis 100 sccm eingeleitet wird.

17. Ein Verfahren gemäß einem der Ansprüche 13 bis 16, wobei das Substrat durch das Prozessgas geätzt wird und das Spaltgas mit einer Strömungsrate zugeführt wird, welche die Ätzleistung nicht nachteilig beeinflusst.

Revendications

1. Appareil de traitement par plasma comprenant :

une chambre de traitement (10) ;

une source d'énergie qui excite un gaz de traitement à l'intérieur de la chambre de traitement à l'état de plasma ;

un support de substrat (14, 12) supportant un substrat (32) à l'intérieur de la chambre de traitement pour être traité par le gaz de traitement, le support de substrat présentant une surface extérieure, le substrat étant supporté en relation de suspension par rapport à la surface extérieure du support ;

un anneau de focalisation (16) entourant le support de substrat , l'anneau de focalisation ayant une surface intérieure formant un espacement (30) entre la surface extérieure du support de substrat et l'anneau de focalisation, l'espacement (30) étant en communication de fluide avec l'intérieur de la chambre de traitement, le substrat s'étendant sur une partie au moins de l'anneau de focalisation de telle sorte que la surface intérieure de l'anneau de focalisation soit disposée à l'intérieur d'une périphérie extérieure du substrat ; et

une alimentation en gaz de blocage (50) en communication de fluide avec l'espacement par l'intermédiaire d'une pluralité de canaux d'alimentation radiaux (38) dans le support, présentant des sortie dans l'espacement, l'alimentation en gaz servant à fournir un gaz de blocage dans l'espacement pour bloquer une migration du gaz de traitement et de ses produits dérivés volatiles vers l'espacement pendant le traitement du substrat.

2. Appareil de traitement par plasma selon la revendication 1, dans lequel la source d'alimentation électrique comprend une bobine (18) qui couple de façon inductive une énergie RF à travers une fenêtre diélectrique (20) pour former un plasma à haute densité dans la chambre de traitement.

3. Appareil de traitement par plasma selon la revendication 1 ou 2, dans lequel l'alimentation en gaz de blocage fournit de l'hélium à l'espacement.

4. Appareil de traitement par plasma selon les revendications 1, 2 ou 3, dans lequel l'alimentation en gaz de blocage fournit le gaz de blocage suivant un débit de 60 à 100 sccm.

5. Appareil de traitement par plasma selon l'une quelconque des revendications 1 à 4, dans lequel l'espacement est annulaire et il existe huit canaux d'alimentation radiaux.

6. Appareil de traitement par plasma selon l'une quelconque des revendications 1 à 5, dans lequel les canaux d'alimentation (38) sont dotés de parties de restriction de flux (40, 41, 42) pour contrôler le débit du gaz de blocage.

7. Appareil de traitement par plasma selon l'une quelconque des revendications 1 à 6, dans lequel le support est composé d'un élément porteur (12) et d'une pince électrostatique (14) et les canaux (38) se trouvent dans la pince.

8. Appareil de traitement par plasma selon l'une quelconque des revendications 1 à 7, dans lequel l'anneau de focalisation est fait en céramique et l'espacement est inférieur à 6,4 mm ( ¼ de pouce) entre les surfaces intérieure et extérieure.

9. Support de substrat pour un appareil de traitement par plasma comportant une chambre de traitement (10), une source d'énergie qui excite un gaz de traitement à l'intérieur de la chambre de traitement à l'état de plasma pour traiter un substrat et une alimentation en gaz de blocage (50), le support de substrat comportant : une surface de support de substrat qui supporte un substrat (32) à l'intérieur de la chambre de traitement pendant son utilisation, la surface de support de substrat étant délimitée par une surface extérieure et le substrat étant supporté en relation de suspension par rapport à la surface du support pour s'étendre au-delà de la surface extérieure ;
   un anneau de focalisation (16) supporté sur et entourant la surface de support de substrat, l' anneau de focalisation présentant une surface intérieure formant un espacement entre la surface extérieure du support de substrat et l'anneau de focalisation, l'espacement étant en communication de fluide avec l'intérieur de la chambre de traitement lorsque le support de substrat est monté dans la chambre de traitement, le substrat s'étendant sur au moins une partie de l'anneau de focalisation de telle sorte que la surface intérieure de l'anneau de focalisation soit placée vers l'intérieur d'une périphérie extérieure du substrat ; et
   des moyens de communication de fluide comportant une pluralité de canaux radiaux (38) dans le support comportant des orifices de sortie dans l'espacement pour établir une communication de fluide entre l'espacement et l'alimentation en gaz de blocage qui sert, en fonctionnement, à fournir un gaz de blocage à l'espacement selon un débit qui est suffisant pour bloquer la migration du gaz de traitement et de ses produits dérivés volatiles vers l'espacement pendant le traitement d'un substrat supporté sur la surface de support de substrat.

10. Support de substrat selon la revendication 9, dans lequel la surface de support de substrat est pourvue d'un mandrin électrostatique (14) et l'anneau de focalisation est en céramique.

11. Support de substrat selon la revendication 9, dans lequel l'espacement (30) est annulaire et il existe huit canaux radiaux dans le mandrin ayant des orifices de sortie dans l'espacement.

12. Support de substrat selon la revendication 11, dans lequel les canaux de gaz de blocage sont pourvus de parties de restriction de flux (40, 41, 42) pour contrôler le débit du gaz de blocage.

13. Procédé de contrôle d'un dépôt de polymère à l'intérieur d'une chambre de traitement par plasma (10) consistant à :

placer un substrat (32) sur un support de substrat (14, 12) à l'intérieur de la chambre de traitement (10) ;

exciter un gaz de traitement à l'intérieur de la chambre de traitement à l'état de plasma pour traiter le substrat ; et

introduire un gaz de blocage fourni par une alimentation en gaz (50) dans un espacement (30) compris entre le support de substrat et un anneau de focalisation (16) supporté par, et entourant, le support de substrat, le substrat s'étendant sur une partie au moins de l'anneau de focalisation de telle sorte qu'une surface interne de l'anneau de focalisation définissant l'espacement soit placée vers l'intérieur d'une périphérie extérieure du substrat, le gaz de blocage étant fourni par l'intermédiaire de canaux radiaux (38) dans le support conduisant aux orifices de sortie dans l'espacement suivant un débit suffisant pour rendre minimale la migration du gaz de traitement et de ses produits dérivés volatiles vers l'espacement.

14. Procédé selon la revendication 13, dans lequel le support est composé d'un élément porteur (12) et d'un mandrin électrostatique (14), le substrat est maintenu en place dans la chambre de traitement par le mandrin électrostatique, et le gaz de traitement est excité à l'état de plasma par une source d'énergie qui fournit une énergie RF à une bobine qui couple de façon inductive l'énergie RF à travers une fenêtre diélectrique pour former un plasma de haute densité dans la chambre de traitement.

15. Procédé selon la revendication 13 ou 14, dans lequel le gaz de blocage introduit dans l'espacement comprend de l'hélium.

16. Procédé selon l'une quelconque des revendications 13 à 15, dans lequel le gaz de blocage est introduit suivant un débit de 60 à 100 sccm..

17. Procédé selon l'une quelconque des revendications 13 à 16, dans lequel le substrat est gravé par le gaz de traitement et le gaz de blocage est fourni suivant un débit qui n'affecte pas de façon négative la performance des bords de gravure.

Drawing